Add lifetime extensions

osu.Game/Rulesets/UI/HitObjectContainer.cs

@@ -58,6 +58,16 @@ namespace osu.Game.Rulesets.UI
         /// </remarks>
         public event Action<HitObject> HitObjectUsageFinished;
 
+        /// <summary>
+        /// The amount of time prior to the current time within which <see cref="HitObject"/>s should be considered alive.
+        /// </summary>
+        public double PastLifetimeExtension { get; set; }
+
+        /// <summary>
+        /// The amount of time after the current time within which <see cref="HitObject"/>s should be considered alive.
+        /// </summary>
+        public double FutureLifetimeExtension { get; set; }
+
         private readonly Dictionary<DrawableHitObject, IBindable> startTimeMap = new Dictionary<DrawableHitObject, IBindable>();
         private readonly Dictionary<HitObjectLifetimeEntry, DrawableHitObject> drawableMap = new Dictionary<HitObjectLifetimeEntry, DrawableHitObject>();
         private readonly LifetimeEntryManager lifetimeManager = new LifetimeEntryManager();
@@ -179,7 +189,7 @@ namespace osu.Game.Rulesets.UI
         protected override bool CheckChildrenLife()
         {
             bool aliveChanged = base.CheckChildrenLife();
-            aliveChanged |= lifetimeManager.Update(Time.Current, Time.Current);
+            aliveChanged |= lifetimeManager.Update(Time.Current - PastLifetimeExtension, Time.Current + FutureLifetimeExtension);
             return aliveChanged;
         }
 

osu.Game/Rulesets/UI/Playfield.cs

@@ -240,6 +240,42 @@ namespace osu.Game.Rulesets.UI
                 p.KeepAllAlive();
         }
 
+        /// <summary>
+        /// The amount of time prior to the current time within which <see cref="HitObject"/>s should be considered alive.
+        /// </summary>
+        public double PastLifetimeExtension
+        {
+            get => HitObjectContainer.PastLifetimeExtension;
+            set
+            {
+                HitObjectContainer.PastLifetimeExtension = value;
+
+                if (!nestedPlayfields.IsValueCreated)
+                    return;
+
+                foreach (var nested in nestedPlayfields.Value)
+                    nested.PastLifetimeExtension = value;
+            }
+        }
+
+        /// <summary>
+        /// The amount of time after the current time within which <see cref="HitObject"/>s should be considered alive.
+        /// </summary>
+        public double FutureLifetimeExtension
+        {
+            get => HitObjectContainer.FutureLifetimeExtension;
+            set
+            {
+                HitObjectContainer.FutureLifetimeExtension = value;
+
+                if (!nestedPlayfields.IsValueCreated)
+                    return;
+
+                foreach (var nested in nestedPlayfields.Value)
+                    nested.FutureLifetimeExtension = value;
+            }
+        }
+
         /// <summary>
         /// The cursor currently being used by this <see cref="Playfield"/>. May be null if no cursor is provided.
         /// </summary>